There are few useful pediatric outcome measures available to assess hospital quality of care. Mortality, the basis for many adult comparisons, is rare in pediatrics. Complication measures lack construct validity and adequate severity adjustment. This proposal will develop a new class of outcome measures, the conditional length of stay (CLOS), for use in pediatrics. The investigation has 5 specific aims. (1) The patterns of LOS will be studied using engineering and statistical reliability theory in 20 common pediatric medical and surgical conditions or procedures to identify those that display a pattern of "extended" LOS given "prolonged" LOS. Extended LOS is defined as a distribution of stay wherein the longer a patient stays in the hospital, the longer that patient will stay in the hospital. We will test the hypothesis that discharges after a specified initial LOS display a declining hazard rate, using a statistic developed by Hollander and Proschan. Data sources will include State discharge data from Pennsylvania and New York from 1996 and 97, and the 1996 and 97 National MQProfile Database of MediQual, Inc. (2) The association between declining discharge rate and the presence of complications in the pediatric population will be examined to determine the optimal cut-point for use with the CLOS measure. (3) The construct validity of CLOS as a quality of care measure will be demonstrated by defining the association between CLOS and other outcome measures such as the death rate, the complication rate, and the failure-to-rescue rate. If CLOS increases with longer LOS, this statistic can be used as a marker for quality of care. The relationship between hospital and provider characteristics and CLOS will be studied. (4) It is hypothesized that hospitals with traditional markers for pediatric excellence, such as children's hospitals, or pediatric teaching hospitals, will have shorter CLOS, after adjustment for case-mix and severity, than general hospitals treating similar pediatric patients but without such markers of excellence. Finally, (5) policy recommendations and guidelines for the use of CLOS to measure pediatric quality of care will be developed.